Challenge Criterium 320 Tire - Clincher $74.99
Supple and smooth.
Similar to the rest of Challenge's high end clinchers, the Criterium 320 tire uses an open tubular design. We know that it sounds like an oxymoron -- a clincher tubular. However, the benefits of Challenge open tubulars are astounding. They use the same handmade construction techniques and materials as Challenge's tubulars, with the only difference being that instead of a sewn construction, beads are actually formed by folding the casing around a durable fiber known as Aramid. This material is used for the tire beads for the same reason that it's used for bulletproof vests -- it provides lightweight, compact strength. Aramid prevents rolling-off in corners and adds to the cumulative strength of the tire.
The Criterium 320 Clincher relies on its proven tread pattern in order to provide both low rolling-resistance and incredible grip. Longitudinal ribs run down the center, with a herringbone structure on either side. And like the good old days, this legendary tread pattern is still glued by hand to the casing after the casing has been tensioned. The logic behind this is that, when a tread made separate from the casing, it rides better and with less rolling-resistance. The reason behind this is that it doesn't get deformed by the inflation of the tire.
Below the tread, Challenge applied its classic corespun cotton casing. Essentially, this means that the casing fibers are made by twisting staple cotton fibers around a central filament core, creating one yarn from multiple fibers. As a result, the material is between 40 and 50% stronger than typically spun materials, while retaining a similar, if not lower, overall weight. This results in a thin, light, and flexible case that is super-supple. The thread count is 320 threads per inch (TPI), which is the highest in the Challenge line. This not only creates the smoothest ride available in a clincher design, but it also contributes to the Criterium 320's low weight (200g per tire).
And to provide protection against flats, a thin corespun polyester belt -- the same material that makes the casing -- is sandwiched between the casing and the tread. It's also glued on when the casing is under pressure. Challenge calls this its Puncture Protection System (PPS), giving a little added protection under the tread while leaving the sidewalls thin and supple.
The Challenge Criterium 320 Clincher measures 700c x 23mm and is available in the colors Black/black and Black/tan.